Polymer additive compositions comprising highly versatile thermoplastic nucleators

ABSTRACT

Bicyclic nucleator compounds that provide highly versatile nucleation benefits for different polyolefins are provided. Such nucleator compounds provide very high peak crystallization temperatures and significantly reduced crystallization cycle time for certain thermoplastic formulations with or without the presence of other calcium stearate and/or peroxide components within the same type of formulation. Furthermore, such inventive nucleator compounds exhibits very little if any fugitivity from such thermoplastic formulations thereby providing excellent processing characteristics as well as excellent nucleation capabilities for a variety of different thermoplastic resins, independent of the presence of different, potentially necessary, additives (such as calcium stearate). Thermoplastic compositions as well as thermoplastic additive packages comprising such inventive nucleator compounds are also contemplated within this invention.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of co-pending application Ser.No. 09/864,460, filed on May 23, 2001. This parent application is hereinentirely incorporated by reference.

FIELD OF THE INVENTION

[0002] This invention relates to types of bicyclic nucleator compoundsthat provide highly versatile nucleation benefits for differentthermoplastics. Such nucleator compounds provide very high peakcrystallization temperatures and short crystallization cycle time forcertain thermoplastic formulations with or without the presence of othercalcium stearate and/or peroxide components within the same type offormulation. Furthermore, such inventive nucleator compounds exhibitvery little, if any, fugitivity from such thermoplastic formulationsthereby providing excellent processing characteristics as well asexcellent nucleation capabilities for a variety of differentthermoplastic resins, independent of the presence of different,potentially necessary, additives (such as calcium stearate).Thermoplastic compositions as well as thermoplastic additive packagescomprising such inventive nucleator compounds are also contemplatedwithin this invention.

BACKGROUND OF THE PRIOR ART

[0003] All U.S. patents cited below are herein entirely incorporated byreference.

[0004] As used herein, the term “thermoplastic” is intended to mean apolymeric material that will melt upon exposure to sufficient heat butwill retain its solidified state, but not prior shape without use of amold or like article, upon sufficient cooling. Specifically, as well,such a term is intended solely to encompass polymers meeting such abroad definition that also exhibit either crystalline orsemi-crystalline morphology upon cooling after melt-formation.Particular types of polymers contemplated within such a definitioninclude, without limitation, polyolefins (such as polyethylene,polypropylene, polybutylene, and any combination thereof), polyamides(such as nylon), polyurethanes, polyesters (such as polyethyleneterephthalate), and the like (as well as any combinations thereof).

[0005] Thermoplastics have been utilized in a variety of end-useapplications, including storage containers, medical devices, foodpackages, plastic tubes and pipes, shelving units, and the like. Suchbase compositions, however, must exhibit certain physicalcharacteristics in order to permit widespread use. Specifically withinpolyolefins, for example, uniformity in arrangement of crystals uponcrystallization is a necessity to provide an effective, durable, andversatile polyolefin article. In order to achieve such desirablephysical properties, it has been known that certain compounds andcompositions provide nucleation sites for polyolefin crystal growthduring molding or fabrication. Generally, compositions containing suchnucleating compounds crystallize at a much faster rate than unnucleatedpolyolefin. Such crystallization at higher temperatures results inreduced fabrication cycle times and a variety of improvements inphysical properties, such as, as one example, stiffness.

[0006] Such compounds and compositions that provide faster and or higherpolymer crystallization temperatures are thus popularly known asnucleators. Such compounds are, as their name suggests, utilized toprovide nucleation sites for crystal growth during cooling of athermoplastic molten formulation. Generally, the presence of suchnucleation sites results in a larger number of smaller crystals. As aresult of the smaller crystals formed therein, clarification of thetarget thermoplastic may also be achieved, although excellent clarity isnot always a result. The more uniform, and preferably smaller, thecrystal size, the less light is scattered. In such a manner, the clarityof the thermoplastic article itself can be improved. Thus, thermoplasticnucleator compounds are very important to the thermoplastic industry inorder to provide enhanced clarity, physical properties and/or fasterprocessing.

[0007] As an example of one type of nucleator, dibenzylidene sorbitolderivative compounds are typical nucleator compounds, particularly forpolypropylene end-products. Compounds such as1,3-O-2,4-bis(3,4-dimethylbenzylidene) sorbitol, available from MillikenChemical under the trade name Millad(g) 3988 (hereinafter referred to as3,4-DMDBS), provide excellent nucleation characteristics for targetpolypropylenes and other polyolefins. Other well known compounds includesodium benzoate, sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate (from Asahi Denka Kogyo K.K., known as and hereinafterreferred to as NA-11), aluminumbis[2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate] (also fromAsahi Denka Kogyo K.K., which is understood to be known as andhereinafter referred to as NA-21), talc, and the like. Such compoundsall impart high polyolefin crystallization temperatures; however, eachalso exhibits its own drawback for large-scale industrial applications.

[0008] Other acetals of sorbitol and xylitol are typical nucleators forpolyolefins and other thermoplastics as well. Dibenzylidene sorbitol(DBS) was first disclosed in U.S. Pat. No. 4,016,118 by Hamada, et al.as effective nucleating and clarifying agents for polyolefin. Sincethen, large numbers of acetals of sorbitol and xylitol have beendisclosed, including bis(p-methylbenzylidene) sorbitol (hereinafterreferred to as 4-MDBS). Representative references of such othercompounds include Mahaffey, Jr., U.S. Pat. No. 4,371,645 [di-acetals ofsorbitol having at least one chlorine or bromine substituent].

[0009] As noted above, another example of the effective nucleatingagents are the metal salts of organic acids. Wijga in U.S. Pat. Nos.3,207,735, 3,207,736, and 3,207,738, and Wales in U.S. Pat. Nos.3,207,737 and 3,207,739, suggest that aliphatic, cycloaliphatic, andaromatic carboxylic, dicarboxylic or higher polycarboxylic acids, andcorresponding anhydrides and metal salts, are effective nucleatingagents for polyolefin. They further state that benzoic acid typecompounds, in particular sodium benzoate, are the best nucleating agentsfor their target polyolefins.

[0010] Another class of nucleating agents was suggested by Nakahara, etal. in U.S. Pat. No. 4,463,113, in which cyclic bis-phenol phosphateswas disclosed as nucleating and clarifying agents for polyolefin resins,as well as U.S. Pat. No. 5,342,868 to Kimura, et al. Compounds that arebased upon these technologies are marketed under the trade names NA-11and NA-21, discussed above.

[0011] Furthermore, a certain class of bicyclic compounds, such asbicyclic dicarboxylic acid and salts, have been taught as polyolefinnucleating agents as well within Patent Cooperation Treaty ApplicationWO 98/29494, 98/29495 and 98/29496, all assigned to Minnesota Mining andManufacturing. The best working examples of this technology are embodiedin disodium bicyclo[2.2.1]heptene dicarboxylate and camphanic acid.

[0012] The efficacy of nucleating agents is typically measured by thepeak crystallization temperature of the polymer compositions containingsuch nucleating agents. A high polymer peak crystallization isindicative of high nucleation efficacy, which generally translates intofast processing cycle time and more desirable physical properties, suchas stiffness/impact balance, etc., for the fabricated parts. Compoundsmentioned above all impart relatively high polyolefin crystallizationtemperatures; however, each also exhibits its own drawback forlarge-scale industrial applications.

[0013] For example, it is very desirable that the effective nucleatingcompounds exhibit a very high peak crystallization temperature, forexample, above 125° C. within a test homopolymer polypropylene that,when unnucleated exhibits a number of different characteristics such asa density of about 0.9 g/cc, a melt flow of about 12 g/10 min, aRockwell Hardness (R scale) of about 90, a tensile strength of about4,931 psi, an elongation at yield of about 10%, a flexural modulus ofabout 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and adeflection temperature at 0.46 mPa of about 93° (which provides ahomopolymer exhibiting an isotacticity of between about 96 and 99%),wherein said peak crystallization temperature is measured bydifferential scanning calorimetry in accordance with ASTM Test MethodD3417-99 modified to measure at heating and cooling rates of 20°C./minute. Such a polypropylene homopolymer provides an effective testsubject for this purpose due to the general uniformity of productavailable (and thus better uniformity in peak crystallizationtemperature, etc., results, therein for samples of such athermoplastic), as well as the widespread use of such a thermoplastic.Of course, it should be well understood by the ordinarily skilledartisan that such a test homopolymer is not the only thermoplastic inwhich the inventive nucleating agent may be present; it is solely a testformulation in order to determine the highest peak crystallizationtemperature, etc., for certain inventive nucleating agents under certainconditions. Of the nucleating agents mentioned above, only camphanicacid exhibits such a high polymer peak crystallization temperaturewithin such a test homopolymer propylene formulation. However, as shownin the comparative examples within this invention, camphanic acidexhibits very poor thermal stability, where it tends to vaporize andaccumulate on the surface of plastic processing equipments duringprocessing. This phenomenon is generally referred to as “plate out”within the plastics industry. The “plate out” effect of this additivemake it impractical for any commercial use. Thus, the combination ofvery high polymer peak crystallization temperature (thus highlyefficient nucleation) and a low degree of fugitivity (and thus highthermal stability and low plate-out characteristics) within the targetpolymers (e.g., preferably polyolefins such as polypropylene) is verydesirable within the plastics industry, particularly where the peakcrystallization temperature is measured above 126° C. within ahomopolymer polypropylene measured by differential scanning calorimetryat a rate of 20° C./minute. So far, such a combination has not beenprovided within this intensively studied area of polymer nucleatingagents.

[0014] Beyond high polymer crystallization temperature and lowfugitivity, there are a number of other performance characteristicsimportant for the practical use of such nucleating agents. For example,one of great interest is the compatibility of such compounds withdifferent additives widely used within typical polyolefin (e.g.,polypropylene, polyethylene, and the like) plastic articles. As notedpreviously, calcium stearate compatibility is particularly important.Unfortunately, most of the nucleator compounds noted above (such assodium benzoate, NA-11, disodium bicyclo[2.2.1]heptene dicarboxylate)exhibit deleterious nucleating efficacy when present with such compoundswithin polyolefin articles. It is generally speculated that the calciumion from the stearate transfers positions with the sodium ions of thenucleating agents, rendering the nucleating agents ineffective for theirintended function. As a result, such compounds sometimes exhibitunwanted plate-out characteristics and overall reduced nucleationperformance as measured, for example, by a decrease in crystallizationtemperature during and after polyolefin processing of greater than 2° C.as compared to the peak crystallization temperature of the nucleatedpolymer with no calcium stearate present therein. In order to avoidcombinations of these standard nucleators and calcium salts, othernonionic acid neutralizers, such as dihydrotalcite (DHT4-A), would benecessary for use in conjunction with such nucleators. Such acombination, however, has proven problematic in certain circumstancesdue to worsened aesthetic characteristics (e.g., higher haze), andcertainly higher costs in comparison with standard calcium salts.

[0015] Other problems encountered with the standard nucleators notedabove include inconsistent nucleation due to dispersion problems,resulting in stiffness and impact variation in the polyolefin article.Substantial uniformity in polyolefin production is highly desirablebecause it results in relatively uniform finished polyolefin articles.If the resultant article does not contain a well dispersed nucleatingagent, the entire article itself may suffer from a lack of rigidity andlow impact strength.

[0016] Furthermore, storage stability of nucleator compounds andcompositions is another potential problem with thermoplastic nucleatorsand thus is of enormous importance. Since nucleator compounds aregenerally provided in powder or granular form to the polyolefinmanufacturer, and since uniform small particles of nucleating agents areimperative to provide the requisite uniform dispersion and performance,such compounds must remain as small particles through storage. Certainnucleators, such as sodium benzoate, exhibit high degrees ofhygroscopicity such that the powders made therefrom hydrate easilyresulting in particulate agglomeration. Such agglomerated particles mayrequire further milling or other processing for deagglomeration in orderto achieve the desired uniform dispersion within the targetthermoplastic. Furthermore, such unwanted agglomeration due to hydrationmay also cause feeding and/or handling problems for the user.

[0017] Some nucleating agents, such as certain DBS derivatives, exhibitcertain practical deficiencies such as a tendency to plate-out at highprocessing temperatures. DBS derivatives, particularly where thearomatic rings are mono-substituted, show much improved thermalstability. However, such compounds also tend to exhibit undesirablemigratory properties coupled with problematic organoleptic deficiencieswithin certain polyolefin articles. As a result, such compounds cannotbe widely utilized in some important areas, such as within medicaldevices (e.g., syringes, and the like) and food packaging.

[0018] These noticeable problems have thus created a long-felt need inthe plastics industry to provide such compounds that do not exhibit theaforementioned problems and provide excellent peak crystallizationtemperatures and low fugitivity for the target polyolefins themselves.To date, the best compounds for this purpose remain those noted above.To date, nucleators exhibiting exceptionally high peak crystallizationtemperatures, low fugitivity, low hygroscopicity, excellent thermalstability, and non-migratory properties within certain targetpolyolefins, and compatibility with most standard polyolefin additives(such as, most importantly, calcium stearate) have not been available tothe plastics industry.

OBJECTS OF THE INVENTION

[0019] Therefore, an object of the invention is to provide a polyolefinnucleating agent that provides excellent high peak crystallizationtemperatures to polypropylene articles and formulations and alsoexhibits extremely low fugitivity (excellent thermal stability, lowplate-out). A further object of the invention is to provide a nucleatorcompound and compositions thereof that exhibit excellent calciumstearate compatibility within target polyolefin articles andformulations. Also, the inventive compounds must exhibit excellent lowhygroscopicity in order to accord an extremely good shelf-stableadditive composition. Another objective of this invention is to providea nucleating compound and composition that exhibits low migration onceincorporated within polyolefin articles. Another objective of thisinvention is to provide a nucleating agent and composition that exhibitslittle or no foul taste and/or odor within polyolefin articles. Anotherobject of the invention is to provide a nucleator compound that affectsthe crystallization process within the target polyolefin polymer in sucha manner that the resultant lamellar structure is highly unique(extremely thick) in comparison with other nucleated polypropylenearticles and formulations such that said polyolefin exhibits very highstiffness properties. Additionally, it is an object of this invention toprovide a nucleator compound or composition that may be used in variouspolyolefin media for use in myriad end-uses.

[0020] Accordingly, this invention encompasses a nucleating agent whichinduces a peak crystallization temperature of at least 125° C.(preferably, at least 125.5; more preferably, at least 126; still morepreferably, at least 126.5; and most preferably at least 127; preferablysuch a temperature is as high as possible, up to the level of aself-nucleated test homopolymer polypropylene resin, such as at about137-8° C., with a high temperature of about 134° C. most preferred) fora test homopolymer polypropylene formulation, wherein the unnucleatedtest homopolymer propylene exhibits a density of about 0.9 g/cc, a meltflow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, atensile strength of about 4,931 psi, an elongation at yield of about10%, a flexural modulus of about 203 ksi, an Izod impact strength ofabout 0.67 ft-lb/in, and a deflection temperature at 0.46 mPa of about93°, and wherein said formulation is extruded then molded into plaqueshaving dimensions of about 51 mm×76 mm×1.27 mm, wherein said peakcrystallization temperature is measured by differential scanningcalorimetry in accordance with a modified ASTM Test Method D3417-99 atheating and cooling rates of 20° C./minute, and wherein said nucleatingagent also exhibits no appreciable fugitivity from said test homopolymerpolypropylene formulation during compounding of said test homopolymerpolypropylene formulation.

[0021] Also encompassed within this invention is a nucleating agentwhich induces a crystallization half time (t_(1/2)) of at most 2.0minutes in a test homopolymer polypropylene formulation, wherein theunnucleated test homopolymer propylene exhibits a density of about 0.9g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) ofabout 90, a tensile strength of about 4,931 psi, an elongation at yieldof about 10%, a flexural modulus of about 203 ksi, an Izod impactstrength of about 0.67 ft-lb/in, and a deflection temperature at 0.46mPa of about 93° C., and wherein said formulation is extruded thenmolded into plaques having dimensions of about 51 mm×76 mm×1.27 mm,wherein said t_(1/2) is measured by differential scanning calorimetry ata constant crystallization temperature of about 140° C., and whereinsaid nucleator also exhibits no appreciable fugitivity from saidpolypropylene formulation.

[0022] Additionally, this invention also encompasses a nucleating agentwhich induces a standard peak crystallization temperature of at least123.5° C. in a test homopolymer polypropylene formulation, wherein theunnucleated test homopolymer polypropylene exhibits a density of about0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (Rscale) of about 90, a tensile strength of about 4,931 psi, an elongationat yield of about 10%, a flexural modulus of about 203 ksi, an Izodimpact strength of about 0.67 ft-lb/in, and a deflection temperature at0.46 mPa of about 93° C., and wherein said formulation is extruded thenmolded into plaques having dimensions of about 51 mm×76 mm×1.27 mm,wherein said peak crystallization temperature measured by differentialscanning calorimetry in accordance with a modified ASTM Test MethodD3417-99 at heating and cooling rates of 20° C./minute and wherein saidnucleating agent is present in at most 1500 ppm, wherein said polymernucleator exhibits no appreciable fugitivity from said polypropyleneformulation during compounding of said polypropylene, and wherein saidnucleating agent induces said peak crystallization temperature in saidpolypropylene formulation when no calcium stearate is present, andwherein said nucleating agent induces a comparative peak crystallizationtemperature of at most 2° C. lower than said standard peakcrystallization for the same polypropylene formulation when at least 800ppm of calcium stearate is present. Furthermore, such a compoundexhibits a very low hygroscopicity as well.

[0023] Additionally, this invention encompasses a nucleating agent whichproduces an effective nucleation density of greater than 7×10⁹nuclei/cm³ at an isothermal crystallization temperature of about 148° C.in a test homopolymer polypropylene formulation comprising saidnucleating agent, wherein the unnucleated test homopolymer propyleneexhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min,a Rockwell Hardness (R scale) of about 90, a tensile strength of about4,931 psi, an elongation at yield of about 10%, a flexural modulus ofabout 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and adeflection temperature at 0.46 mPa of about 93°, and wherein saidformulation is extruded then molded into plaques having dimensions ofabout 51 mm×76 mm×1.27 mm, and wherein said nucleating agent alsoexhibits no appreciable fugitivity from said test homopolymerpolypropylene formulation during compounding of said test homopolymerpolypropylene formulation comprising said nucleating agent.

[0024] Still further encompassed within this invention is a nucleatingagent which exhibits a nucleation effectiveness factor (NEF) of greaterthan 0.06 in a test homopolymer polypropylene formulation having adensity of about 0.9 g/cc, a melt flow of about 12 g/l 0 min, a RockwellHardness (R scale) of about 90, a tensile strength of about 4,931 psi,an elongation at yield of about 10%, a flexural modulus of about 203ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflectiontemperature of 0.46 mPa at about 93° C., wherein said formulation isextruded and then molded into plaques having dimensions of about 51mm×76 mm×1.27 mm.

[0025] It should also be well understood and appreciated by one ofordinary skill within this art that the inventive nucleating agent isdefined above as performing to a certain degree within a test polymerformulation, and is not required to be a component within such a testpolymer formulation. Thus, although such an inventive nucleating agentmust perform to a certain level within a test homopolymer propylene, itmay be present within any other type of polymer (such as athermoplastic), including blends of polymers. The particular polymerswithin which such an inventive nucleating is effective and useful arelisted below in greater detail.

[0026] The bicyclic compounds are defined as organic compounds thatcontain two or more rings wherein at least two of the said rings shareat least two nonadjacent atoms.

[0027] Some particular, non-limiting examples of such novel nucleatorcompounds include the metal or organic salts of saturated [2.2.1]bicyclic dicarboxylates, and most preferably of these types of compoundsconforming to Formula (I)

[0028] wherein M₁ and M₂ are the same or different and are independentlyselected from the group consisting of metal or organic cations, and R₁,R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, and R₁₀ are individually selected fromthe group consisting of hydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy,C₁-C₉ alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl,alkylphenyl, and geminal or vicinal C₁-C₉ carbocyclic. Preferably, themetal cations are selected from the group consisting of calcium,strontium, barium, magnesium, aluminum, silver, sodium, lithium,rubidium, potassium, and the like. Within that scope, group I and groupII metal ions are generally preferred. Among the group I and II cations,sodium, potassium, calcium and strontium are preferred, wherein sodiumand calcium are most preferred. Furthermore, the M₁ and M₂ groups mayalso be combined to form a single metal cation (such as calcium,strontium, barium, magnesium, aluminum, and the like). Although thisinvention encompasses all stereochemical configurations of suchcompounds, the cis configuration is preferred wherein cis-endo is themost preferred embodiment. The preferred embodiment polyolefin articlesand additive compositions for polyolefin formulations comprising atleast one of such compounds are also encompassed within this invention.

[0029] The term “no appreciable fugitivity” as used as one descriptionwithin this invention is intended to encompass nucleators which exhibitvery high heat stabilities (and thus very low plate-out) within testpolypropylene formulations. Therefore, a weight loss of nucleatorcompound during a thermal stability test of at most 5% is encompassedwithin this term. Such thermal stability testing is described in greaterdetail below.

DETAILED DESCRIPTION OF THE INVENTION

[0030] As noted above, in order to develop a proper polyolefin nucleatorcompound or composition for industrial applications, a number ofimportant criteria need to be met. The inventive nucleating agents meetall of these important requirements very well. For instance, asdiscussed in greater detail below, these inventive salts provideexcellent high peak crystallization temperatures in a variety ofpolyolefin formulations, particularly within random copolymerpolypropylene (hereinafter RCP) and homopolymer polypropylene(hereinafter HP). As a result, such inventive salts provide excellentmechanical properties for polyolefin articles without the need for extrafillers and rigidifying additives, and desirable processingcharacteristics such as improved (shorter) cycle time. The salts alsoshow much improved hygroscopicity comparing to prior art and thusgranular or powder formulations of such a salt do not agglomerate orclump together. Lastly, such inventive salts do not interactdeleteriously with calcium stearate additives.

[0031] Such properties are highly unexpected and unpredictable,particularly in view of the closest prior art, the WO 98/29494 referencediscloses nucleation and clarification additives for polyolefin articlesincluding unsaturated [2.2.1]dicarboxylate salts; however, there is noexemplification of a saturated dicarboxylate salt of this type. Theclosest embodiment within that art is identified as disodiumbicyclo[2.2.1]heptene dicarboxylate. After intensive investigations, ithas been determined that, quite unexpectedly, as discussed below ingreater detail, the hydrogenation of such compounds provides vastlyimproved nucleation efficacy for the inventive compounds and within theinventive polyolefin compositions. It has now been found that thesaturation of Diels-Alder reaction products to form dicarboxylate salts,and in particular, without intending to limit the scope of theinvention, saturated bicyclic dicarboxylate salts, provide unforeseenbenefits for polyolefin nucleation processes.

[0032] As indicated in Table 1, below, the peak crystallizationtemperatures provided target polyolefin articles with these inventivesaturated compounds are from about 2.5 to about 5° C. above that for therelated unsaturated compounds. Such dramatic improvements are simplyunexpected and are unpredictable from any known empirical or theoreticalconsiderations. Furthermore, significant improvements in hygroscopicityof the saturated compounds were also unexpectedly observed. Suchunpredictable improvements are of great practical significance asdiscussed before.

[0033] Yet another surprise was the improved compatibility between theseinventive saturated compounds and typical acid scavenger salt compoundsutilized within polyolefin formulations and articles, such as calciumand lithium stearate. Such compatibility, coupled with the high peakcrystallization temperatures available from the inventive compounds,thus provides a highly desirable thermoplastic nucleator compound.Furthermore, the ability to provide extremely high nucleation densitymeasurements (above an order of magnitude than typical nucleating agentsat various isothermal crystallization temperatures) is highly desirableand previously unattainable as well.

[0034] The inventive salts are thus added within the target polyolefinin an amount from about 50 ppm to about 20,000 ppm by weight in order toprovide the aforementioned beneficial characteristics, most preferablyfrom about 200 to about 4000 ppm. Higher levels, e.g., 50% or more byweight, may also be used in a masterbatch formulation. Optionaladditives within the inventive salt-containing composition, or withinthe final polyolefin article made therewith, may include plasticizers,antistatic agents, stabilizers, ultraviolet absorbers, and other similarstandard polyolefin thermoplastic additives. Other additives may also bepresent within this composition, most notably antioxidants, antistaticcompounds, antimicrobials (preferably silver-based ion-exchangecompounds, such as ALPHASAN® antimicrobials available from Milliken &Company), perfumes, chlorine scavengers, and the like. Such additives,and others not listed, are well known to those skilled in the art.

[0035] The term polyolefin or polyolefin resin is intended to encompassany materials comprised of at least one polyolefin compound. Preferredexamples include isotactic and syndiotactic polypropylene, polyethylene,poly(4-methyl)pentene, polybutylene, and any blends or copolymersthereof, whether high or low density in composition. The polyolefinpolymers of the present invention may include aliphatic polyolefins andcopolymers made from at least one aliphatic olefin and one or moreethylenically unsaturated co-monomers. Generally, the co-monomers, ifpresent, will be provided in aminor amount, e.g., about 10 percent orless or even about 5 percent or less, based upon the weight of thepolyolefin (e.g. random copolymer polypropylene), but copolymerscontaining up to 25% or more of the co-monomer (e.g., impact copolymers)are also envisaged. Other polymers or rubber (such as EPDM or EPR) mayalso be compounded with the polyolefin to obtain the aforementionedcharacteristics. Such co-monomers may serve to assist in clarityimprovement of the polyolefin, or they may function to improve otherproperties of the polymer. Other examples include acrylic acid and vinylacetate, etc. Examples of olefin polymers whose transparency can beimproved conveniently according to the present invention are polymersand copolymers of aliphatic monoolefins containing 2 to about 6 carbonatoms which have an average molecular weight of from about 10,000 toabout 2,000,000, preferably from about 30,000 to about 300,000, such as,without limitation, polyethylene, linear low density polyethylene,isotactic polypropylene, syndiotactic polypropylene, crystallineethylene propylene copolymer, poly(1-butene), polymethylpentene,1-hexene, 1-octene, and vinyl cyclohexane. The polyolefins of thepresent invention may be described as basically linear, regular polymersthat may optionally contain side chains such as are found, for instance,in conventional low density polyethylene.

[0036] Although polyolefins are preferred, the nucleating agents of thepresent invention are not restricted to polyolefins, and may also givebeneficial nucleation properties to polyesters such as polyethyleneterephthalate (PET), polybutylene terephthalate (PBT), and polyethylenenaphthalate (PEN), as well as polyamides such as Nylon 6, Nylon 6,6, andothers. Generally, any thermoplastic composition having some crystallinecontent may be improved with the nucleating agents of the presentinvention.

[0037] The compositions of the present invention may be obtained byadding the inventive saturated bicyclic dicarboxylic salt (orcombination of salts or composition comprising such salts) to thethermoplastic polymer or copolymer and merely mixing the resultantcomposition by any suitable means. Alternatively, a concentratecontaining as much as about 20 percent by weight of the inventivesaturated [2.2.1] salt in a polyolefin masterbatch comprising therequired acid scavenger may be prepared and be subsequently mixed withthe target resin. Furthermore, the inventive compositions (with otheradditives potentially) may be present in any type of standardthermoplastic (e.g., polyolefin, most preferably) additive form,including, without limitation, powder, prill, agglomerate, liquidsuspension, and the like, particularly comprising dispersion aids suchas polyolefin (e.g., polyethylene) waxes, stearate esters of glycerin,montan waxes, mineral oil, and the like. Basically, any form may beexhibited by such a combination or composition including suchcombination made from blending, agglomeration, compaction, and/orextrusion.

[0038] The composition may then be processed and fabricated by anynumber of different techniques, including, without limitation, injectionmolding, injection blow molding, injection stretch blow molding,injection rotational molding, extrusion, extrusion blow molding, sheetextrusion, film extrusion, cast film extrusion, foam extrusion,thermoforming (such as into films, blown-films, biaxially orientedfilms), thin wall injection molding, and the like into a fabricatedarticle.

PREFERRED EMBODIMENTS OF THE INVENTION

[0039] Examples of particularly preferred fluid dispersions within thescope of the present invention are presented below.

[0040] Production of Inventive Salts

EXAMPLE A Disodium bicyclo[2.2.1]heptane-2,3-dicarboxylate

[0041] To a solution of disodiumbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate (10.0 g, from example 3) inwater (100 g) was added 0.5 g palladium on activated carbon (5 wt %).The mixture was transferred into a Parr reactor and was subjected tohydrogenation (50 psi, room temperature) for 8 hours. The activatedcarbon was filtered out. Water is removed in vacuo at 75° C. Theresulting product was dried and milled (m.p>300° C.).

EXAMPLE 2 Calcium bicyclo[2.2.1]heptane-2,3-dicarboxylate

[0042] To a solution of disodium bicyclo[2.2.1]heptane-2,3-dicarboxylate(22.6 g, 0.1 mol) in water (150 g) was added a solution of calciumchloride dihydrate (14.7 g, 0.1 mol) in water (100 g). The mixturestirred at 60° C. for 2 hours. The resulting white precipitate wasfiltered. The white powdery product was dried and milled (m.p. >300°C.).

EXAMPLE 3 (Comparative) Disodiumbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate

[0043] To a suspension of endo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylicanhydride (16.4 g, 0.1 mol) in water (100 g) was added sodium hydroxide(8.0 g, 0.2 mol) at room temperature. The mixture was then stirred at80° C. for 2 hour. A clear, homogeneous solution was obtained. Water wasremoved in vacuo at 75° C. and the resulting white crystalline productwas dried and milled (m.p. >300° C.).

[0044] Other lithium, rubidium, potassium, strontium, barium, andmagnesium [2.2.1]heptane dicarboxylate salts were also prepared in likemanners for testing. Commercial samples of NA-11, NA-21, 3,4-DMDBS, and4-MDBS were used in this evaluation without further purification andtreatment. Camphanic acid (purity higher than 98%) was purchased fromAldrich Chemical company. It was used without further purification andtreatment.

[0045] Nucleation Efficacy Tests

[0046] Thermoplastic compositions (plaques) were produced comprising theadditives from the Examples above and sample homopolymer polypropylene(HP) resin plaques, produced dry blended in a Welex mixer at ˜2000 rpm,extruded through a single screw extruder at 400-450° F., and pelletized.Accordingly, one kilogram batches of target polypropylene were producedin accordance with the following table:

HOMOPOLYMER POLYPROPYLENE COMPOSITION

[0047] Component Amount Polypropylene homopolymer (Himont Profax ® 6301)1000 g Irganox ® 1010, Primary Antioxidant (from Ciba)  500 ppmIrgafos ® 168, Secondary Antioxidant (from Ciba) 1000 ppm Acid Scavengeras noted Nucleating Agent as noted

[0048] The base HP [having a density of about 0.9 g/cc, a melt flow ofabout 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensilestrength of about 4,931 psi, an elongation at yield of about 10%, aflexural modulus of about 203 ksi, an Izod impact strength of about 0.67ft-lb/in, and a deflection temperature at 0.46 mPa of about 93° C., aswell as an expected isotacticity of between about 96 and 99% throughxylene solubles analysis] and all additives were weighed and thenblended in a Welex mixer for 1 minute at about 1600 rpm. All sampleswere then melt compounded on a Killion single screw extruder at a rampedtemperature from about 204° to 232° C. through four heating zones. Themelt temperature upon exit of the extruder die was about 246° C. Thescrew had a diameter of 2.54 cm and a length/diameter ratio of 24: 1.Upon melting the molten polymer was filtered through a 60 mesh (250micron) screen. Plaques of the target polypropylene were then madethrough extrusion into an Arburg 25 ton injection molder. The molder wasset at a temperature anywhere between 190 and 260° C., with a range of190 to 240° C. preferred, most preferably from about 200 to 230° C. andat an injection speed within the range of between about 1 and about 5cm³/second. The plaques had dimensions of about 51 mm×76 mm×1.27 mm, andthe mold had a mirror finish which was transferred to the individualplaques. The mold cooling circulating water was controlled at atemperature of about 25° C.

[0049] Testing for nucleating effects and other important criteria wereaccomplished through the formation of plaques of clarified polypropylenethermoplastic resin. These plaques were formed through the processoutlined above with the specific compositions listed above in the aboveTable.

[0050] These plaque formulations are, of course, merely preferredembodiments of the inventive article and method and are not intended tolimit the scope of this invention. The resultant plaques were thentested for peak crystallization temperatures (by Differential ScanningCalorimetry). Crystallization is important in order to determine thetime needed to form a solid article from the molten polyolefincomposition. Generally, a polyolefin such as polypropylene has acrystallization temperature of about 110° C. at a cooling rate of 20°C./min. In order to reduce the amount of time needed to form the finalproduct, as well as to provide the most effective nucleation for thepolyolefin, the best nucleator compound added will invariably alsoprovide the highest crystallization temperature for the final polyolefinproduct. The nucleation composition efficacy, particular polymer peakcrystallization temperature (T_(c)), was evaluated by using a modifieddifferential scanning procedure based upon the test protocol ASTMD3417-99 wherein the heating and cooling rates utilized have beenaltered to 20° C./minute each. Thus, to measure the peak crystallizationtemperatures of the samples, the specific polypropylene compositionswere heated from 60° C. to 220° C. at a rate of 20° C. per minute toproduce molten formulations and held at the peak temperature for 2minutes. At that time, the temperature was then lowered at a rate of 20°C. per minute until it reached the starting temperature of 60° C. foreach individual sample. The important crystallization temperatures werethus measured as the peak maxima during the individual crystallizationexotherms for each sample. After allowing the plaques to age for 24hours at room temperature, haze values were measured according to ASTMStandard Test Method D1003-61 “Standard Test Method for Haze andLuminous Transmittance of Transparent Plastics” using a BYK GardnerHazegard Plus.

[0051] The following Table lists the peak crystallization temperaturesand haze results for the sample plaques prepared with the additivesnoted above (with certain acid scavengers and levels thereof as well aslevels of nucleating agent used therein specified for each sample;Samples 5-10, below included 2500 ppm each of the nucelating agent):EXPERIMENTAL TABLE 1 Performance of Bicyclic Nucleators in PolypropyleneHomopolymer Sam- Peak T_(c) Haze ple # Nucleator Conc. (ppm) (° C.) (%)1 Example A (1000 ppm)^(a) 126 34 2 Example A (2500 ppm)^(a) 128 30 3Example B (1000 ppm)^(a) 125 48 4 Example B (2500 ppm)^(a) 127 45 5Lithium bicyclo[2.2.1]heptane dicarboxylate^(a) 123 56 6 Potassiumbicyclo[2.2.1]heptane dicarboxylate^(b) 125 67 7 Rubidiumbicyclo[2.2.1]heptane dicarboxylate^(b) 123 55 8 Magnesiumbicyclo[2.2.1]heptane dicarboxylate^(a) 117 78 9 Bariumbicyclo[2.2.1]heptane dicarboxylate^(a) 121 71 10 Strontiumbicyclo[2.2.1]heptane dicarboxylate^(a) 124 56 11 - - - (ComparativeControl)^(a) 110 68 12 Example C (Comparative) (1000 ppm)^(a) 122 50 13Example C (Comparative) (2500 ppm)^(a) 123 46 14 3,4-DMDBS (2500ppm)^(a) 123 11 15 NA-11 (1000 ppm)^(c) 124 32 16 NA-21 (2500 ppm)^(a)123 20 17 Camphanic Acid (2500 ppm)^(b) 127 30

[0052] The data show that inventive nucleating agents in Examples A andB, above, exhibit significantly high polymer peak crystallizationtemperatures and simultaneous low haze measurements.

[0053] Another important test for nucleation efficacy is thecrystallization half-time (t_(1/2)). This measurement was conducted onDSC where the specific polypropylene composition was heated from 60° C.to 220° C. at a rate of 20° C. per minute to produce a moltenformulation and held at the peak temperature for 2 minutes. At thattime, the temperature was then lowered quickly to 140° C., where thesample was held. The exotherm of crystallization was measured with time.The time where exactly one-half of the heat of crystallization isgenerated was recorded as the crystallization half time. Shortercrystallization half time is indicative of higher nucleation efficacy.In a practical sense, a shorter crystallization half time is anindicator of a shorter cycle time, and thus of significant value.EXPERIMENTAL TABLE 2 Crystallization Half Time in Homopolymer Sample #Loading (from Experimental Table 1) (ppm) t_(1/2) (minutes) 13(Comparative) 2500 4.50  2 2500 0.98  4 2500 1.40

[0054] The data show that the inventive compounds of Examples A and Bexhibit significantly shorter crystallization half times.

[0055] Thermal Stability (Fugitivity) Test

[0056] Thermal stability of is an important criteria for polymeradditives. Additives lacking thermal stability would cause plate out andother processing issues. Stability tests are conducted on aThermogravimetric Analyzer from TA Instruments. Roughly 10 mg of drysample is added to the stainless steel sample cell. The sample cell isthen blanketed with nitrogen. Sample is allowed to equilibrate for 5minutes at 25° C. The temperature is then raised at 20° C./min ramp rateuntil it reaches 500° C. Weight loss in percentage versus temperature isrecorded for the sample nucleator from within the sample polypropyleneas a result of such thermal stability testing. Polypropylene istypically processed between 200-250° C. and a weight loss of the samplenucleator in excess of 5% at 250° C. is generally considered asunsuitable for use since the remaining amounts would be insufficient forproper and necessary nucleation to occur. The weight loss data forcamphanic acid and disodium [2.2.1]cycloheptane dicarboxylate is shownbelow: EXPERIMENTAL TABLE 3 Thermal Stability Results % weight loss ofTemperature % Weight loss of Example A Camphanic acid 200° C. 0.9% 10%250° C. 1.2% 47% 300° C. 1.4% 89%

[0057] The data indicate that although camphanic acid exhibitscomparable polymer peak crystallization temperature, it lacks thenecessary thermal stability for practical commercial use.

[0058] Calcium Stearate Compatibility Test

[0059] In this test, the nucleators were tested in formulations with andwithout calcium stearate. The nucleation efficacy of the nucleators ineach formulation was studied by measuring polymer crystallizationtemperature. The formulations and testing conditions are identical withthose discussed above. A drop of 2° C. or more is considered a failure.EXPERIMENTAL TABLE 4 Calcium Stearate (CaSt) Compatibility Test SampleCaSt Load- Peak T_(c) # Nucleator Conc. (ppm) ing (ppm) Peak T_(c)Change 18 Example A (2500 ppm)^(d)  0 128 — 19 Example A (2500 ppm)^(e)800 128 ˜0 20 Example B (2500 ppm)^(d)  0 127 — 21 Example B (2500ppm)^(e) 800 127 ˜0 22 NA-11^(d)  0 124 — 23 NA-11^(e) 800 121   3 24Example C^(d)  0 123 — 25 ExampleC^(e) 800 121   2 26 Camphanic Acid^(f) 0 127 — 27 Camphanic Acid^(e) 800 124   3

[0060] The data show that the inventive nucleators in Examples A andExample B pass the compatibility test with calcium stearate.

[0061] Hygroscopicity Test:

[0062] These tests were carried out on the milled products to giveadequate surface area for moisture uptake. Two grams of each examplewere spread out on a watch glass and weighed immediately after drying ina vacuum oven. The samples were then placed in a controlled humidity(65%) environment and the weight was taken each day for 7 days. Thepercent weight gain was defined as the percent moisture uptake.Experimental Table 5 below summarizes the results: EXPERIMENTAL TABLE 5Hygroscopicity Test Data Sample # Nucleating Agent Weight Gain (% w/w)28 Example A 1% 29 Example B 0% 30 Example C (Comparative) 8%

[0063] It is clear from the above data that saturation of Example 3reduces the hygroscopicity over that of the prior art significantly, andthe use of calcium as the metal reduces the moisture uptake to zero.

[0064] Nucleation Efficacy in Polyester:

[0065] The inventive additives were also tested as nucleating agents forpolyester. Additives were compounded with a C. W. Brabender TorqueRheometer at 5000 ppm into Shell Cleartuff™ 8006 PET bottle grade resinhaving an Intrinsic Viscosity of 0.80. All resin was dried to less than20 ppm water. Samples were taken, pressed, and rapidly cooled into 20-40mil films. All samples were dried at 150° C. under vacuum for 6 hoursprior to analysis. The samples were analyzed under nitrogen on a PerkinElmer System 7 differential scanning calorimeter using a heating andcooling rate of 20° C./min. The polymer peak crystallization temperaturewas measured as described before. The data is shown in ExperimentalTable 6 below: EXPERIMENTAL TABLE 6 Polyester Nucleating Results SamplePeak Cryst. Temp. (° C.) Control 155 Example C 184 Example A 194

[0066] Thus, the inventive saturated compound exhibited much improvednucleation of polyester over the control with no nucleator compound andthe unsaturated nucleator compound.

[0067] Retort Extraction Test:

[0068] Plaques, as prepared above, were subjected an extraction test asoutlined in the following procedure:

[0069] Seven plaques were cut into nine strips each to give a totalsurface area of approximately 600 cm². These strips were rinsed withdeionized water and allowed to dry. They were then placed into a glassextraction vessel and covered with 200 ml of deionized water. The glassvessels and their contents were autoclaved for 60 minutes at 120° C.,and were allowed to cool and settle for 24 hours. After settling,approximately 60 ml of the extraction solution was transferred to aclean beaker, and 10 ml of this solution was filtered through a 0.8-μmfilter fitted to a syringe. The filtrate was collected in a 1-cm quartzcuvette. The cuvette and contents were scanned for peak UV absorbancesin the wavelength range 220-240 nm and 241-350 nm, after a suitabledeionized water blank had been scanned. Such a test provides indicationsof the effectiveness of the resultant thermoplastic with regards to theextractability of any contents of the plastic itself and thus is a goodindicator as to the usefulness of the thermoplastic product fordifferent types of end-uses. The lower the extraction level, the moreuseful such thermoplastic is for food contact, for example. EXPERIMENTALTABLE 7 Extraction Performance of Bicyclic Nucleators in PolypropyleneHomopolymer Additive Conc. Peak Absorbance, Peak Absorbance, Additives(ppm) 220-240 nm 241-350 nm Control (no nucleator) — 0.019 0.006 ExampleA 2500 0.012 0.004 4-MDBS 2200 0.336 0.183

[0070] The data demonstrate that the inventive product in Example 1shows extraction levels comparable to thermoplastic samples containingno nucleator at all and thus indicates that such thermoplastic may beuseful for various end-uses.

[0071] Nucleation Density

[0072] One method of evaluating the nucleating efficiency of anucleating agent in a given resin is to calculate the density ofnucleating sites per unit volume of polymer as well as comparing suchdensity measurements at differing isothermal crystallizationtemperatures. The greater the density of nucleating sites, the betterthe nucleating agent. The higher the ratio of densities betweendifferent isotherms, the more versatile the nucleating agent.

[0073] For these purposes, the effective nucleation densities for theinventive and comparative nucleating agents were calculated by combiningisothermal crystallization kinetic data measured using differentialscanning calorimetry and spherulitic growth rate data measured withoptical microscopy. A Perkin Elmer DSC-7 was calibrated with an indiummetal standard at a heating rate of 20C/min. Polymer samples with athickness of 250+/−50 microns and a weight of 5.0+/−0.5 mg were encasedin aluminum pans. The pans were then heated from 60° C. to 220° C. at2⁰° C./min, held 2 minutes, rapidly cooled to the isothermalcrystallization temperature, and then held at the isothermalcrystallization temperature until the crystallization was complete.

[0074] The relative crystallinity, C, as a function of time, t, wascalculated as demonstrated in [1]. Crystallization Kinetic data weremodeled using the Avrami Equation: 1−C=exp(−Kt^(n)), where K and n areconstants. The Avrami equation was rewritten in logarithmic form:ln(−ln(1−C))=ln K+n ln t and then linear regression was used to find thebest values of K and n for relative crystallinities between 0.05 and0.5. The linear spherulitic growth rate of polypropylene at a giventemperature, G, was calculated using the equation G=1.62×10¹⁰exp(−0.20T), where T has units of degrees Celsius and G has units of μm/sec [1].For example, G(140° C.)=0.0112 μm/sec.

[0075] The effective nucleation density, N, was calculated according toN=3K′/ 4πG³, where K′ is an Avrami rate constant for the case ofthree-dimensional growth at a linear growth rate. K′ was calculated fromK using the following relation: K′=ln2/(ln2/K)^(3/n) [2]. For example,at an isothermal crystallization temperature of 140° C., homopolymerpolypropylene nucleated with 0.1% NA-11UF had Avrami rate constantsn=3.21 and K=0.0484 min^(−3.21). The corresponding value of K′ was0.0576 min⁻³=2.67×10⁻⁷ sec⁻³.

[0076] The following Table shows the nucleation density measurements forvarious nucleating agents at 140 and 148° C. isotherms. An asterisk forNA-21 indicates that the nucleation density was too low to be measured.EXPERIMENTAL TABLE 8 Nucleation Density Measurements Isothermal T_(c)Nucleation Density Nucleating Agent (° C.) (nuc/cm³) 1000 ppm Ex. A^(g)140 6 E 11 1000 ppm NA-11^(h) 140 4 E 10 2200 ppm NA-21^(g) 140 4 E 92500 ppm Camphanic Acid^(i) 140 3 E 11 1000 ppm Ex. A^(g) 148 1 E 111000 ppm NA-11^(h) 148 2 E 9 2200 ppm Na-21^(g) 148 * 2500 ppm CamphanicAcid^(i) 148 1 E 10

[0077] Thus, the inventive nucleating agent provided an increase innucleation density within the test homopolymer polypropylene at least anorder of magnitude greater than the closest typical polyolefinnucleating agents. Therefore, such an inventive nucleating agent isdefined as one which, at an isothermal T_(c) of about 148° C. of atleast 7E9 (7×10⁹) nuc/cm²; preferably at least 1E10; still morepreferably, at least 5E10; and most preferably at least 1E11, within thetest homopolymer polypropylene formulation as noted above, and which, asnoted above, does not exhibit any appreciable fugitivity from thethermoplastic formulation during compounding thereof.

[0078] Furthermore, it is desirable to measure the effectiveness of agiven nucleating agent over a broad range of temperatures. An excellentmanner of quantifying such effectiveness measurements over such broadtemperature ranges is to calculate a what we have termed a nucleationeffectiveness factor. Such a factor (hereinafter referred to as NEF) is,for a given additive, defined as the ratio of the nucleation densityprovided by a nucleation agent at 148° to the nucleation densityprovided by the same nucleation agent at 140° C. [in other wordsNEF=N(148° C.)/N(140° C.)]. A nucleating agent which exhibits a highernucleation effectiveness factor supplies a large number of heterogeneousnuclei to the polymer over a broad temperature range, which leads tofaster polymer crystallization over such a expanded range oftemperatures. As noted below in the accompanying Table, and using theresults in Experimental Table 8, above, such NEF measurements are asfollows: EXPERIMENTAL TABLE 9 NEF Measurements as Delineated fromEXPERIMENTAL TABLE 8 Nucleating Agent NEF Example A 0.16 NA-11 0.05Camphanic Acid 0.03

[0079] Thus, the inventive nucleating agent is more effective andversatile than the comparative compounds over a broad temperature range.Preferably, such a NEF is thus greater than about 0.06; more preferably,greater than about 0.08; still more preferably greater than about 0.10;and most preferably greater than about 0.12, since the greater thenumber, the greater the versatility of the nucleating agent.

[0080] Having described the invention in detail it is obvious that oneskilled in the art will be able to make variations and modificationsthereto without departing from the scope of the present invention.Accordingly, the scope of the present invention should be determinedonly by the claims appended hereto.

That which is claimed is:
 1. A polymer additive composition comprising anucleating agent which induces a peak crystallization temperature of atleast 125° C. for a test homopolymer polypropylene formulationcomprising said nucleating agent, wherein the unnucleated testhomopolymer propylene exhibits a density of about 0.9 g/cc, a melt flowof about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, atensile strength of about 4,931 psi, an elongation at yield of about10%, a flexural modulus of about 203 ksi, an Izod impact strength ofabout 0.67 ft-lb/in, and a deflection temperature at 0.46 mPa of about93°, and wherein said formulation comprising said nucleating agent isextruded then molded into plaques having dimensions of about 51 mm×76mm×1.27 mm, wherein said peak crystallization temperature is measured bydifferential scanning calorimetry in accordance with a modified ASTMTest Method D3417-99 at heating and cooling rates of 20° C./minute, andwherein said nucleating agent also exhibits no appreciable fugitivityfrom said test homopolymer polypropylene formulation during compoundingof said test homopolymer polypropylene formulation comprising saidnucleating agent, wherein said additive composition is present in a formselected from the group consisting of a powder, a pellet, and a liquid,and wherein said composition also comprises at least one acid scavengerand optionally comprises at least one thermoplastic polymer and at leastone compound selected from the group consisting of plasticizers,antioxidants, antimicrobials, flame retardants, light stabilizers,antistatic agents, blowing agents, colored pigments, and any combinationthereof.
 2. The polymer additive composition of claim 1 wherein saidnucleating agent is a bicyclic compound.
 3. The polymer additivecomposition of claim 2 wherein said bicyclic compound conforms with thestructure of Formula (I)

wherein M₁ and M₂ are the same or different, or M₁ and M₂ are combinedto form a single moiety, and are independently selected from the groupconsisting of metal or organic cations, and R₁, R₂, R₃, R₄, R₅, R₆, R₇,R₈, R₉, and R₁₀ are individually selected from the group consisting ofhydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy, C₁-C₉ alkoxy, C₁-C₉alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl, alkylphenyl,and geminal or vicinal carbocyclic having up to nine carbon atoms.
 4. Apolymer additive composition comprising a nucleating agent which inducesa crystallization cycle time (t_(1/2)) of at most 2.0 minutes in a testhomopolymer polypropylene formulation comprising said nucleating agent,wherein the unnucleated test homopolymer propylene exhibits a density ofabout 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (Rscale) of about 90, a tensile strength of about 4,931 psi, an elongationat yield of about 10%, a flexural modulus of about 203 ksi, an Izodimpact strength of about 0.67 ft-lb/in, and a deflection temperature at0.46 mPa of about 93° C., and wherein said formulation comprising saidnucleating agent is extruded then molded into plaques having dimensionsof about 51 mm×76 mm×1.27 mm, wherein said t_(1/2) cycle time ismeasured by differential scanning calorimetry at a constantcrystallization temperature of about 140° C., and wherein said nucleatoralso exhibits no appreciable fugitivity from said polypropyleneformulation during compounding of said test homopolymer polypropyleneformulation comprising said nucleating agent, wherein said additivecomposition is present in a form selected from the group consisting of apowder, a pellet, and a liquid, and wherein said composition alsocomprises at least one acid scavenger and optionally comprises at leastone thermoplastic polymer and at least one compound selected from thegroup consisting of plasticizers, antioxidants, antimicrobials, flameretardants, light stabilizers, antistatic agents, blowing agents,colored pigments, and any combination thereof.
 5. The polymer additivecomposition of claim 4 wherein said nucleating agent is a bicycliccompound.
 6. The polymer additive composition of claim 5 wherein saidbicyclic compound conforms to the structure of Formula (I)

wherein M₁ and M₂ are the same or different, or M₁ and M₂ are combinedto form a single moiety, and are independently selected from the groupconsisting of metal or organic cations, and R₁, R₂, R₃, R₄, R₅, R₆, R₇,R₈, R₉, and R₁₀ are individually selected from the group consisting ofhydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy, C₁-C₉ alkoxy, C₁-C₉alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl, alkylphenyl,and geminal or vicinal carbocyclic having up to nine carbon atoms.
 7. Apolymer additive composition comprising a nucleating agent which inducesa standard peak crystallization temperature of at least 123.5° C. in atest homopolymer polypropylene formulation comprising said nucleatingagent, wherein the unnucleated test homopolymer polypropylene exhibits adensity of about 0.9 g/cc, a melt flow of about 12 g/10 min, a RockwellHardness (R scale) of about 90, a tensile strength of about 4,931 psi,an elongation at yield of about 10%, a flexural modulus of about 203ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflectiontemperature at 0.46 mPa of about 93° C., and wherein said formulationcomprising said nucleating agent is extruded then molded into plaqueshaving dimensions of about 51 mm×76 mm×1.27 mm, wherein said peakcrystallization temperature measured by differential scanningcalorimetry in accordance with a modified ASTM Test Method D3417-99 atheating and cooling rates of 20° C./minute, wherein said nucleator ispresent in at most 1500 ppm, wherein said nucleator agent exhibits noappreciable fugitivity from said polypropylene formulation duringcompounding of said polypropylene formulation with said nucleatingagent, and wherein said nucleating agent further induces said peakcrystallization temperature within said polypropylene formulation whenno calcium stearate is present therein, and wherein said nucleatingagent provides a comparative peak crystallization temperature of at most2° C. lower than said standard peak crystallization for the samepolypropylene formulation when at least 800 ppm of calcium stearate ispresent therein, wherein said additive composition is present in a formselected from the group consisting of a powder, a pellet, and a liquid,and wherein said composition also comprises at least one acid scavengerand optionally comprises at least one thermoplastic polymer and at leastone compound selected from the group consisting of plasticizers,antioxidants, antimicrobials, flame retardants, light stabilizers,antistatic agents, blowing agents, colored pigments, and any combinationthereof.
 8. The polymer additive composition of claim 7 wherein saidnucleating agent is a bicyclic compound.
 9. The polymer additivecomposition of claim 8 wherein said bicyclic compound conforms to thestructure of Formula (I)

wherein M₁ and M₂ are the same or different, or M₁ and M₂ are combinedto from a single moiety, and are independently selected from the groupconsisting of metal or organic cations, and R₁, R₂, R₃, R₄, R₅, R₆, R₇,R₈, R₉, and R₁₀ are individually selected from the group consisting ofhydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy, C₁-C₉ alkoxy, C₁-C₉alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl, alkylphenyl,and geminal or vicinal carbocyclic having up to nine carbon atoms.
 10. Apolymer additive composition comprising a nucleating agent whichproduces an effective nucleation density of greater than 7×10⁹nuclei/cm³ at an isothermal crystallization temperature of about 148° C.in a test homopolymer polypropylene formulation comprising saidnucleating agent, wherein the unnucleated test homopolymer propyleneexhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min,a Rockwell Hardness (R scale) of about 90, a tensile strength of about4,931 psi, an elongation at yield) of about 10%, a flexural modulus ofabout 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and adeflection temperature at 0.46 mPa of about 93°, and wherein saidformulation is extruded then molded into plaques having dimensions ofabout 51 mm×76 mm×1.27 mm, and wherein said nucleating agent alsoexhibits no appreciable fugitivity from said test homopolymerpolypropylene formulation during compounding of said test homopolymerpolypropylene formulation comprising said nucleating agent, wherein saidadditive composition is present in a form selected from the groupconsisting of a powder, a pellet, and a liquid, and wherein saidcomposition also comprises at least one acid scavenger and optionallycomprises at least one thermoplastic polymer and at least one compoundselected from the group consisting of plasticizers, antioxidants,antimicrobials, flame retardants, light stabilizers, antistatic agents,blowing agents, colored pigments, and any combination thereof.
 11. Apolymer additive composition comprising a nucleating agent whichexhibits a nucleation effectiveness factor (NEF) of greater than 0.06 ina test homopolymer polypropylene formulation having a density of about0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (Rscale) of about 90, a tensile strength of about 4,931 psi, an elongationat yield of about 10%, a flexural modulus of about 203 ksi, an Izodimpact strength of about 0.67 ft-lb/in, and a deflection temperature of0.46 mPa at about 93° C., wherein said formulation is extruded and thenmolded into plaques having dimensions of about 51 mm×76 mm×1.27 mm,wherein said additive composition is present in a form selected from thegroup consisting of a powder, a pellet, and a liquid, and wherein saidcomposition also comprises at least one acid scavenger and optionallycomprises at least one thermoplastic polymer and at least one compoundselected from the group consisting of plasticizers, antioxidants,antimicrobials, flame retardants, light stabilizers, antistatic agents,blowing agents, colored pigments, and any combination thereof.
 12. Apolymer additive composition comprising a nucleating agent which inducesa peak crystallization temperature of at least 125° C. for a testhomopolymer polypropylene formulation comprising said nucleating agent,wherein the unnucleated test homopolymer propylene exhibits a density ofabout 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (Rscale) of about 90, a tensile strength of about 4,931 psi, an elongationat yield of about 10%, a flexural modulus of about 203 ksi, an Izodimpact strength of about 0.67 ft-lb/in, and a deflection temperature at0.46 mPa of about 93°, and wherein said formulation comprising saidnucleating agent is extruded then molded into plaques having dimensionsof about 51 mm×76 mm×1.27 mm, wherein said peak crystallizationtemperature is measured by differential scanning calorimetry inaccordance with a modified ASTM Test Method D3417-99 at heating andcooling rates of 20° C./minute, and wherein said nucleating agent alsoexhibits no appreciable fugitivity from said test homopolymerpolypropylene formulation during compounding of said test homopolymerpolypropylene formulation comprising said nucleating agent, wherein saidadditive composition is present in a form selected from the groupconsisting of a powder, a pellet, and a liquid, and wherein saidcomposition also comprises at least one thermoplastic polymer andoptionally at least one compound selected from the group consisting ofplasticizers, antioxidants, acid scavengers, antimicrobials, flameretardants, light stabilizers, antistatic agents, blowing agents,colored pigments, and any combination thereof.
 13. The polymer additivecomposition of claim 12 wherein said nucleating agent is a bicycliccompound.
 14. The polymer additive composition of claim 13 wherein saidbicyclic compound conforms with the structure of Formula (I)

wherein M₁ and M₂ are the same or different, or M₁ and M₂ are combinedto form a single moiety, and are independently selected from the groupconsisting of metal or organic cations, and R₁, R₂, R₃, R₄, R₅, R₆, R₇,R₈, R₉, and R₁₀ are individually selected from the group consisting ofhydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy, C₁-C₉ alkoxy, C₁-C₉alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl, alkylphenyl,and geminal or vicinal carbocyclic having up to nine carbon atoms.
 15. Apolymer additive composition comprising a nucleating agent which inducesa crystallization cycle time (t_(1/2)) of at most 2.0 minutes in a testhomopolymer polypropylene formulation comprising said nucleating agent,wherein the unnucleated test homopolymer propylene exhibits a density ofabout 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (Rscale) of about 90, a tensile strength of about 4,931 psi, an elongationat yield of about 10%, a flexural modulus of about 203 ksi, an Izodimpact strength of about 0.67 ft-lb/in, and a deflection temperature at0.46 mPa of about 93° C., and wherein said formulation comprising saidnucleating agent is extruded then molded into plaques having dimensionsof about 51 mm×76 mm×1.27 mm, wherein said t_(1/2) cycle time ismeasured by differential scanning calorimetry at a constantcrystallization temperature of about 140° C., and wherein said nucleatoralso exhibits no appreciable fugitivity from said polypropyleneformulation during compounding of said test homopolymer polypropyleneformulation comprising said nucleating agent, wherein said additivecomposition is present in a form selected from the group consisting of apowder, a pellet, and a liquid, and wherein said composition alsocomprises at least one thermoplastic polymer and optionally at least onecompound selected from the group consisting of plasticizers,antioxidants, acid scavengers, antimicrobials, flame retardants, lightstabilizers, antistatic agents, blowing agents, colored pigments, andany combination thereof.
 16. The polymer additive composition of claim15 wherein said nucleating agent is a bicyclic compound.
 17. The polymeradditive composition of claim 16 wherein said bicyclic compound conformsto the structure of Formula (I)

wherein M₁ and M₂ are the same or different, or M₁ and M₂ are combinedto form a single moiety, and are independently selected from the groupconsisting of metal or organic cations, and R₁, R₂, R₃, R₄, R₅, R₆, R₇,R₈, R₉, and R₁₀ are individually selected from the group consisting ofhydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy, C₁-C₉ alkoxy, C₁-C₉alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl, alkylphenyl,and geminal or vicinal carbocyclic having up to nine carbon atoms.
 18. Apolymer additive composition comprising a nucleating agent which inducesa standard peak crystallization temperature of at least 123.5° C. in atest homopolymer polypropylene formulation comprising said nucleatingagent, wherein the unnucleated test homopolymer polypropylene exhibits adensity of about 0.9 g/cc, a melt flow of about 12 g/10 min, a RockwellHardness (R scale) of about 90, a tensile strength of about 4,931 psi,an elongation at yield of about 10%, a flexural modulus of about 203ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflectiontemperature at 0.46 mPa of about 93° C., and wherein said formulationcomprising said nucleating agent is extruded then molded into plaqueshaving dimensions of about 51 mm×76 mm×1.27 mm, wherein said peakcrystallization temperature measured by differential scanningcalorimetry in accordance with a modified ASTM Test Method D3417-99 atheating and cooling rates of 20° C./minute, wherein said nucleator ispresent in at most 1500 ppm, wherein said nucleator agent exhibits noappreciable fugitivity from said polypropylene formulation duringcompounding of said polypropylene formulation with said nucleatingagent, and wherein said nucleating agent further induces said peakcrystallization temperature within said polypropylene formulation whenno calcium stearate is present therein, and wherein said nucleatingagent provides a comparative peak crystallization temperature of at most2° C. lower than said standard peak crystallization for the samepolypropylene formulation when at least 800 ppm of calcium stearate ispresent therein, wherein said additive composition is present in a formselected from the group consisting of a powder, a pellet, and a liquid,and wherein said composition also comprises at least one thermoplasticpolymer and optionally at least one compound selected from the groupconsisting of plasticizers, antioxidants, acid scavengers,antimicrobials, flame retardants, light stabilizers, antistatic agents,blowing agents, colored pigments, and any combination thereof.
 19. Thepolymer additive composition of claim 18 wherein said nucleating agentis a bicyclic compound.
 20. The polymer additive composition of claim 19wherein said bicyclic compound conforms to the structure of Formula (I)

wherein M₁ and M₂ are the same or different, or M₁ and M₂ are combinedto from a single moiety, and are independently selected from the groupconsisting of metal or organic cations, and R₁, R₂, R₃, R₄, R₅, R₆, R₇,R₈, R₉, and R₁₀ are individually selected from the group consisting ofhydrogen, C₁-C₉ alkyl, hydroxyl, C₁-C₉ alkoxy, C₁-C₉ alkoxy, C₁-C₉alkyleneoxy, amine, and C₁-C₉ alkylamine, halogen, phenyl, alkylphenyl,and geminal or vicinal carbocyclic having up to nine carbon atoms.
 21. Apolymer additive composition comprising a nucleating agent whichproduces an effective nucleation density of greater than 7×10⁹nuclei/cm³ at an isothermal crystallization temperature of about 148° C.in a test homopolymer polypropylene formulation comprising saidnucleating agent, wherein the unnucleated test homopolymer propyleneexhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min,a Rockwell Hardness (R scale) of about 90, a tensile strength of about4,931 psi, an elongation at yield) of about 10%, a flexural modulus ofabout 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and adeflection temperature at 0.46 mPa of about 93°, and wherein saidformulation is extruded then molded into plaques having dimensions ofabout 51 mm×76 mm×1.27 mm, and wherein said nucleating agent alsoexhibits no appreciable fugitivity from said test homopolymerpolypropylene formulation during compounding of said test homopolymerpolypropylene formulation comprising said nucleating agent, wherein saidadditive composition is present in a form selected from the groupconsisting of a powder, a pellet, and a liquid, and wherein saidcomposition also comprises at least one thermoplastic polymer andoptionally at least one compound selected from the group consisting ofplasticizers, antioxidants, acid scavengers, antimicrobials, flameretardants, light stabilizers, antistatic agents, blowing agents,colored pigments, and any combination thereof.
 22. A polymer additivecomposition comprising a nucleating agent which exhibits a nucleationeffectiveness factor (NEF) of greater than 0.06 in a test homopolymerpolypropylene formulation having a density of about 0.9 g/cc, a meltflow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, atensile strength of about 4,931 psi, an elongation at yield of about10%, a flexural modulus of about 203 ksi, an Izod impact strength ofabout 0.67 ft-lb/in, and a deflection temperature of 0.46 mPa at about93° C., wherein said formulation is extruded and then molded intoplaques having dimensions of about 51 mm×76 mm×1.27 mm, wherein saidadditive composition is present in a form selected from the groupconsisting of a powder, a pellet, and a liquid, and wherein saidcomposition also comprises at least one thermoplastic polymer andoptionally at least one compound selected from the group consisting ofplasticizers, antioxidants, acid scavengers, antimicrobials, flameretardants, light stabilizers, antistatic agents, blowing agents,colored pigments, and any combination thereof.